Research on co-existence and traceability in the UK

Several co-existence studies are currently underway in the United Kingdom, largely with a focus on the growing of oilseed rape and maize. Results will be delivered forseeably in the second half of 2006.

In populations and harvested yields of oilseed rape, there are three ways in which impurities occur: by presence in the original supply from the seed company; by contamination from leftover feral (i.e. volunteer)populations from previous crops; and by cross-pollination from other cources (other feral, or crop, oilseed rape). A strategy to address the volunteer populations which settle in fields (due to the incidental dropping of seed during harvesting, and due to the dormancy of these dropped seeds) is of great importance for the long-term management of impurities. In the arable seedbank, oilseed rape is one of the most widely represented species; any new varieties of this crop which arise - including GM varieties - are likely to be incorporated into the seedbank.

In order to design a decision tool for the evaluation, and management, of the presence of GM seed in the seedbank and in harvested seed, this project seeks to formulate a predictive model of the residence times and population densities of volunteers.

For oilseed rape, mathematical models exist already for GM contamination occurring through the original seed lot or through volunteers; these models will be refined by the incorporation of within-field spatial distribution patterns of plants and seed, of gene-flow patterns between GM and non-GM volunteers, of the effects of male-sterile volunteers arising from some modern varieties, and of the large amount of (presently incomplete) datasets dealing with the lifecycle of oilseed rape and with practices of weed control.

The individual, practical, test-oriented approach to plant lifecycle biology developed at SCRI will form the supporting skeleton of the model, which will be formulated with reference to available information on the distribution, and persistence, of GM seeds and plants in the field, and which will be vaildated by sampling fields in which more than one type of volunteer oilseed rape is represented.

Research output is expected to be:

a predictive model (incorporating gene flow) of GM impurities in oilseed rape, both seedbank and seed;

a sampling methodology, detecting impurities at different frequencies in fields;

practical management options, keeping impurities below specified levels and with the least use of chemical herbicides; and

an economic assessment of the various options.

In national and European discussions on GM crops, this product will be a source of information and will facilitate on-farm management tools, in the case of GM crops being grown commercially.

The goal of the project is to formulate an applicable model of the movement of pollen among maize plants, and addresses the specific cultivation conditions in the UK. Relying on the molecular tracking of marker genes in the field, the model will provide the basic information for recommendations intended to prevent cross-pollination in cultivation practice.

Cross-pollination in maize is studied on 40 sites.In eight dispersed locations in England and Wales (each location consists of five sites and a meteorological station), defined genotypes of maize will be grown. At various distances between pollen donors and recipients, cobs will be sampled and pollen will be trapped. The dispersal of this pollen will be investigated using DNA analysis, while molecular, meteorological and agronomic information will be recorded during a period of four years. Combining geographical, meteorological and agronomic data, a Gaussian plume model of pollen flow will be constructed, and the predictive uses of this model will be tested. Recommendations will be made based on supporting statistics.

This study is the first of its kind for maize in the UK. For agronomic, environmental and commercial applications, it will make available new and vauable information and tools - importantly, a pollen-flow model applicable to the particulars of crops grown in England and Wales. Additionally, the study will present options intended to avoid, or minimise, cross-pollination, as well as data with which worst-case scenarios of interspecific pollination, and gene transfer, may be formulated.

Measurements will be taken of the biological and environmental factors influencing cross-fertilisation to fields of oilseed rape varieties of a range of male fertility, with emphasis on the maintenance of rigorous statistics on the estimates of whole-field cross-fertilisation. This project addresses specific concerns: crossing from surrounding fields may be much higher to fields of many modern varieties of oilseed rape, in which only a proportion (varying from 20 to 90 percent) of the plants produce pollen, than to fields of fully fertile varieties, in which all plants produce their own pollen.

The whole-field value of cross-fertilisation from one field to another has been shown by research on fully fertile varieties to be generally in the range of 0.1 to 0.3 percent. To date, little information exists on comparative values in partly fertile varieties (for example, partially-restored hybrids and varietal associations), but early trials and theoretical estimates indicate a much higher crossing percentage in these cases. Since high crop-type purity must be guaranteed at harvest, research is now needed to support estimates of whole-field cross-fertilisation in these varieties. Attention should be given particularly to the mechanisms and pollen-transfer vectors responsible (notably, the relative roles of wind and of insects) and to the contribution of regional pollen sources, which are unlikely to be negligible for these varieties.

Cross-pollination in oilseed rape is a difficult aspect for co-existence.In the first year, methodologies for the statistical approach, for detecting low-frequency crossing and for measuring point-to-point transfer of pollen both from nearby and, more widely, in the surrounding area will be established. Subsequently, statistical and biologically-based models will be developed to guide experiments and, ultimately, to predict cross-fertilisation.

At two study sites in the second year, a consistent approach will be applied to estimating whole-field crossing to receptor fields from a source field close to the receptor, and from a source field approximately one kilometre away. The purpose of this configuration is to separate local pollen transfer (which is likely to be detected as a steep decline in crossing from the facing edge of a receptor field near the source) from regional pollen transfer (which is likely to determine crossing to the rest of the nearby receptor field and to the whole of the distant field). Work in this second year will result in a statistically rigorous sampling scheme and in an efficient detection methodology.

In the third and fourth year, and over a wide range of environments, both of these will be used to examine the effects of percentage male fertility on whole-field crossing, on separation distance, on pollen barriers and on the regional topography and configuration of fields. Recommendations will be made for management options to keep the crossing percentage below specified thresholds (e.g. 1 percent, 0.5 percent, 0.1percent).

Desk study on technologies for biological containment of GM and non-GM crops (CB02036)

Recently, Defra has published a study by Reading University ( Dunwell and Ford) which critically reviews effective, current and practical, as well as timely and potentially viable, technologies aimed at reducing the dispersal of transgenes into the environment from GM (and non-GM) crops.

The study is a literature review, and critical assessment, of current knowledge of strategies for biological containment of genes in transgenic and non-transgenic crops. All aspects of technologies for biological containment of GM and non-GM crop plants are critically reviewed, including the evaluation of industrial research efforts in this area.